Windows App SDK 1.2 moving to C# WinRT 2.0, ending .NET 5 support

[BenJKuhn]

The upcoming release of Windows App SDK 1.2 will adopt C# WinRT version 2.0. C# WinRT 2.0-generated projections no longer support .NET 5, as support for .NET 5 ended on May 10th, 2022. As a result, the minimum required .NET version for Windows App SDK 1.2 will be .NET 6.

Ending support for .NET 5 in C# WinRT and the Windows App SDK enables full use of new .NET features that dramatically improve application size, most notably IL Trimming. Future servicing updates to Windows App SDK 1.1 and prior will continue to provide C# API projections based on C# WinRT 1.6 tooling, and will not break compatibility with .NET 5.

You can read more background about the change in C# WinRT here:
CsWinRT 2.0 and .NET 5 · Discussion #1232 · microsoft/CsWinRT (github.com)

For more information about .NET's support lifetime, refer to:
.NET and .NET Core official support policy (microsoft.com)

You can also read more about the end-of-support for .NET 5 here:
.NET 5.0 will reach End of Support on May 10, 2022 - .NET Blog (microsoft.com)